It began a week ago, around noon in Ferguson, Mo. on Saturday, Aug. 9. Eighteen-year-old Michael Brown was fatally shot by a police officer, and his body was left in the street for hours. It took police six days to identify the officer who’d shot and killed Brown, but much is still unknown about the deadly encounter, which triggered widespread protests and clashes with police.

It has all transpired in a majority-black community that already viewed police with skepticism. But Ferguson is hardly the only place where African Americans don’t trust law enforcement; nationally, blacks are far more likely than whites to say that the police treat black people unfairly.

That’s according to a 2013 Pew Research Center survey, which found that 70 percent of black Americans believe they are treated less fairly than whites in their dealings with police. Only 37 percent of whites said they think blacks are treated less fairly by police.

A similar sentiment extends to the courts: 68 percent of black Americans said they believe they are treated less fairly than whites by the courts. Only 27 percent of whites said that, according to Pew.

That massive discrepancy in attitudes has to do, in part, with personal experiences: More than a third of African American respondents told Pew that police had personally treated them unfairly because of race in the past year.

The Pew survey was conducted in August 2013, just weeks after a Florida jury acquitted George Zimmerman of charges of second-degree murder and manslaughter in the shooting death of an unarmed African American teenager, Trayvon Martin.

Young black men in particular believe police officers discriminate against them; a 2013 Gallup poll found that about a quarter of male African Americans between the ages of 18 and 34 believed police had treated them unfairly in the previous 30 days.

Class can play a role, too. In a 1999 study published in Justice Quarterly, people living in white or black middle-class neighborhoods around Washington were less likely to say police treated minorities in their communities unfairly than did blacks living in low-income neighborhoods.